Apparatus and method for monitoring quality metrics associated with a wireless network

ABSTRACT

An apparatus and method for measuring metrics associated with a wireless network is described. One embodiment includes capturing, at a capturing device, a packet transmitted in a wireless network. A congestion indicator is calculated based on a delay associated with the packet.

FIELD OF THE INVENTION

The present invention relates to an apparatus and method for monitoringa wireless network, and more particularly, to an apparatus and methodfor measuring quality associated with a wireless network.

BACKGROUND

As data networks have expanded to include the transmission of variousforms of information such as voice communication, network quality hasbecome increasingly important in network administration. Measures of thequality of a network include, for example, effective bandwidth,congestion, packet delay, jitter, and/or packet loss rate. Because anend-to-end connection within a network can include multiple segmentsand/or links, quality measurements can be determined separately for eachsegment within the end-to-end connection or for the end-to-endconnection as a whole. The quality values associated with a particularlink and/or segment can fluctuate, particularly if the network employs aconnectionless best effort protocol (e.g., internet protocol (IP)).

The variation of quality measurements associated with a link and/orsegment are even more pronounced within a wireless network than in awired network. The quality of a wireless network can change rapidlybecause mobile devices can easily associate and disassociate with thewireless network. For example, a wireless network can rapidly becomecongested resulting in a degradation of quality of service andcomplaints from users when several mobile terminals associate with awireless segment and/or link in a short period of time. The inherentvariation of a wireless network is further exacerbated by the non-linearrelationship between quality measurements and the number of mobileterminals within the wireless network. Because current network protocolsare not designed to adequately measure the quality of a dynamic wirelessnetwork, a need exists for a method and an apparatus for measuringquality within a wireless network.

SUMMARY

Exemplary embodiments of the present invention that are shown in thedrawings are summarized below. These and other embodiments are morefully described in the Detailed Description section. It is to beunderstood, however, that there is no intention to limit the inventionto the forms described in this Summary or in the Detailed Description.One skilled in the art can recognize that there are numerousmodifications, equivalents and alternative constructions that fallwithin the spirit and scope of the invention as expressed in the claims.The present invention provides a system and method for capturing apacket transmitted over a wireless network. A congestion indicator iscalculated based on a delay associated with the captured packet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a mobile monitoring device monitoringwireless communication within an infrastructure wireless network,according to an embodiment of the invention.

FIG. 2 illustrates a mobile monitoring device monitoring packets beingsent and/or received between mobile terminals in an ad-hoc wirelessnetwork, according to an embodiment of the invention.

FIG. 3 is a flowchart that illustrates a method for monitoring awireless network, according to an embodiment of the invention

FIG. 4 is a time line that illustrates delays that can contribute to theoverall delay of a packet when transmitted over a wireless network,according to an embodiment of the invention

FIG. 5 is a graph that illustrates an example embodiment of time clocksassociated with a capturing device and a mobile terminal, according toan embodiment of the invention.

FIG. 6 is a flowchart that illustrates a method for calculating acongestion indicator based on a minimum time delay, according to anembodiment of the invention.

DETAILED DESCRIPTION

A mobile monitoring device (which also can be referred to as a mobilemonitoring agent or capturing device) captures packets that aretransmitted over a wireless network and uses information associated withthe captured packets to calculate various quality metrics. The wirelessnetwork can be, for example, a wireless local area network (wirelessLAN) or a wireless voice over internet protocol (wireless VoIP) network.Quality metrics include, for example, quality-of-service (QoS) metricssuch as packet delay, jitter, and/or packet loss rate, as well asquality metrics such as effective bandwidth and/or congestion. Thepackets can be transmitted within an ad-hoc wireless network or aninfrastructure wireless network between one or more mobile terminalsand/or access points. After the packets are captured, the mobilemonitoring device filters and/or processes the packets to calculatequality metrics that can be associated with the wireless network, amobile terminal(s), and/or an access point(s).

FIG. 1 illustrates a mobile monitoring device 100 monitoring packetsbeing sent and/or received (i.e., communication) within a wirelessnetwork, according to an embodiment of the invention. The mobilemonitoring device 100 includes a memory 102, a processor 104 and atransmitter/receiver module 106. The mobile monitoring device 100 sendsand/or receives signals and/or packets using the transmitter/receivermodule 106 and processes the signals and/or packets using the processor104. In some embodiments, the sending (i.e., transmitting) functionassociated with the transmitter/receiver module 106 and the receivingfunction associated with the transmitter/receiver module 106 can beseparated into different devices (i.e., a separate transmitter moduleand receiver module). The memory 102 is used by the mobile monitoringdevice 100 to temporarily and/or permanently store information and/ordata (e.g., values of parameters associated with packets) to perform anyof the functions associated with the mobile monitoring device 100. Thememory 102 can be any appropriate kind of fixed and/or removable memorysuch as, for example, flash memory or a hard drive.

The mobile monitoring device 100 receives, using thetransmitter/receiver module 106, one or more packets being transmittedby an access point 110 and/or one or more mobile terminals 150-156(i.e., mobile device) over the wireless network. The mobile monitoringdevice 100 calculates a quality metric(s) based on parameters associatedwith one or more packets using the processor 104. The parameters can be,for example, a record and/or information contained within a header of apacket (e.g., packet creation time). The processor 104 within the mobilemonitoring device 100 can be configured to associate the qualitymetric(s) with the access point 110, the wireless network and/or one ormore of the mobile terminals 150-156. The mobile monitoring device 100is also configured to transmit, using the transmitter/receiver module106, the calculated quality metric to, for example, a network managementserver 130, for example, for distribution to a user.

In this embodiment, the mobile terminals 150-156 communicate by sendingand/or receiving packets via the access point 110. For example, mobileterminal 152 can transmit a packet to mobile terminal 154 by first,transmitting the packet to the access point 110. The access point 110then processes the packet and retransmits it so that the packet can bereceived by the mobile terminal 154. The wireless network configurationshown in FIG. 1 can be referred to as an infra-structure mode because itincludes a central device (i.e., access point 110) through whichwireless communication occurs.

Because all communication in the infrastructure wireless network ismanaged through the access point 110, each device (e.g., mobileterminals 150-156 and the mobile monitoring device 100) attempting toengage in communication (e.g., receiving and/or sending packets) overthe wireless network must first associate with the access point 110. Themobile monitoring device 100 and the mobile terminals 150-156 associatewith the access point 110 by listening to and responding to a beaconsignal transmitted by the access point 110. After the mobile terminals150-156 and/or the mobile monitoring device 100 have associated with theaccess point 110, the mobile terminals 150-156 and/or the mobilemonitoring device 100 can send and/or receive packets over the wirelessnetwork. Also, after the mobile terminals 150-156 and/or the mobilemonitoring device 100 have associated with the access point 110, theycan have access to the network management server 130 via switch 120.

The mobile monitoring device 100 captures packets transmitted via radiosignals over a channel with which it is associated. The mobilemonitoring device 100 can be configured to capture packets sent bymobile terminals 150-156 over more than one channel by associating withmore than one channel used by one or more access points 110 and/ormobile terminals 150-156. The mobile terminals 150-156 can be any kindof appropriate mobile terminal capable of sending and/or receiving apacket such as, for example, a computer, a radio, a mobile phone, apersonal digital assistant (PDA), etc. The packet(s) received by themobile monitoring device 100 can be any type of packet such as, forexample, real-time protocol (RTP) packets transmitting over an internetprotocol (IP) wireless LAN. The mobile monitoring device 100 can capturenot only packets, but any variety of communication signals that can betransmitted wirelessly.

The mobile monitoring device 100 can be configured to filter the packets(using the processor 104) that are received at the transmitter/receivermodule 106 to calculate quality metrics based on only certain packets.The mobile monitoring device 100 can calculate quality metrics using,for example, only packets that are transmitted from mobile terminals 152and 154. The mobile monitoring device 100 can filter out packetstransmitting, for example, data so that a quality metric is based onlyon packets transmitting voice communication. The filtering can be basedon filter criteria that are stored, for example, locally on the mobilemonitoring device 100 in the memory 102. The filter criteria can beexecuted using the processor 104.

The mobile monitoring device 100 can calculate a variety of qualitymetrics including, but not limited to, a transport QoS metric, a delaymetric, a jitter metric, and/or a packet loss metric. The mobilemonitoring device 100 can, for example, calculate a packet loss metricby counting the number of packets lost based on packet sequence numbersextracted from, for example, the headers of a group of RTP packets beingtransmitted over a wireless network. The mobile monitoring device 100can also calculate, for example, a jitter metric and/or a delay metricassociated with a packet using standard jitter and/or delay formulasbased on the creation time of the packet and the capture time of thepacket (the time that the packet is captured by the mobile monitoringdevice 100).

In some embodiments, a mobile monitoring device can be configured toreceive a packet transmitted over an ad-hoc wireless network (ratherthan an infrastructure wireless network) and calculate a quality metricbased on information associated with the packet. In an ad-hoc wirelessnetwork a first mobile terminal can send and/or receive a packetdirectly from a second mobile terminal when the first mobile terminaldetects and is acknowledged by the second mobile terminal. The first andsecond mobile terminals create an ad-hoc wireless network through whichthey can send and/or receive packets wirelessly.

FIG. 2 illustrates a mobile monitoring device 200 monitoring packetsbeing sent and/or received between mobile terminals 250 in an ad-hocmode (i.e., peer-to-peer mode). An ad-hoc wireless network differs froman infrastructure wireless network in that communication does not occurthrough an access point. In other words, the mobile monitoring device200 and/or mobile terminals 250 do not associate with an access point.Rather than capturing packets transmitted to and/or from an accesspoint, the mobile monitoring device 200, in an ad-hoc wireless network,captures packets transmitted directly between mobile terminals 250 anduses information associated with those captured packets to generatequality metrics. Other than not communicating via an access point, theoperation of the mobile monitoring device 200 in an ad-hoc wirelessnetwork is substantially the same as the operation of a mobilemonitoring device in an infra-structure wireless network.

FIG. 3 is a flowchart that illustrates a method for monitoring awireless network. The figure shows that a packet (e.g., RTP packet) thatis transmitted over a wireless network is first received at 300. Thepacket can be a packet that was selected from one of several packetsbased on, for example, filter criteria.

After the packet is received at 300, a parameter associated with thepacket is received at 310. The parameter can be any type of parameterassociated with the packet such as a record included in the header ofthe packet. The parameter can also be related to information notcontained in, but associated with the packet, such as a capture timecorresponding to the time that the packet was captured by, for example,a mobile monitoring device. In some embodiments, more than one parameterand/or more than one value for a particular parameter can be received,calculated and/or derived.

After the parameter is received at 310, a quality metric is calculatedbased on the value of the parameter at 320. The quality metric can be,for example, a jitter value or a congestion indicator that can bederived using the value of the parameter. Finally, the calculatedquality metric is associated with a device (e.g. mobile terminal, mobilemonitoring device) and/or the wireless network 330. If the parameter isspecific to, for example, a particular packet, the quality metric can beassociated with a mobile terminal that transmitted that packet. In someembodiments, the quality metric calculated using the parameter can be,for example, associated with the wireless network as a metric that isrepresentative of some aspect of the wireless network.

Although a variety of quality metrics can be calculated based onparameters associated with and/or collected from a packet transmittedover a wireless network, FIGS. 4-6 illustrate several embodimentsrelated to the calculation of a congestion indicator based on parametersassociated with a captured RTP packet. Because back-off delay is anindicator of a congestion level of a wireless network, in theseillustrative embodiments, the congestion indicator is calculated usingdelays, and in particular the back-off delay, associated with an RTPpacket.

FIG. 4 is a time line that illustrates several delays that cancontribute to the overall delay of a packet when transmitted from amobile terminal over a wireless network. From these delays, back-offdelay, and consequently a congestion indicator, can be estimated and/orcalculated. The horizontal axis represents time and is shown asincreasing from left to right.

Specifically, the figure shows an overall delay 450 that includes aprocessing delay 452, back-off delay 454, and transmission delay 456.The back-off delay 454 (the time between time 410 and 420) representsthe time period that a packet is held before being transmitted becauseof network congestion and is thus an indicator of a wireless network'scongestion level. A larger back-off delay 454 indicates a higher levelof wireless network congestion and vice versa. The processing delay 452(the time between time 400 and time 410) is the time that a processorwithin a mobile terminal uses to prepare a packet for transmission. Thetransmission delay 456 (the time between 420 and 430) represents thetime period that a packet is transmitted wirelessly before beingcaptured by, for example, a mobile monitoring device. In otherembodiments, the overall delay 450 can include other delays such as, forexample, interframe space delays.

The figure also shows several times that define the delays 450-456. AnRTP packet is created by a mobile terminal (i.e., creation time) at time400, the packet is ready for transmission at time 410, the packet istransmitted over the wireless network from the mobile terminal at time420, and the RTP packet is captured (i.e., capture time) by, forexample, a mobile monitoring device at time 430. The device thatcaptures the RTP packet can be referred to as a capturing device.

If the processing delay 452 and the transmission delay 456 are verysmall compared (i.e., negligible) with the back-off delay 454, theoverall delay 450 will be substantially equal to the back-off delay 454and thus representative of a congestion level of a wireless network. Inthis scenario, the back-off delay 454, and consequently a congestionindicator, can be estimated by calculating the overall delay 450. Theoverall delay 450 can be calculated as the difference between the packetcreation time 400 and the packet capture time 430. For example, ifcaptured by a mobile monitoring device, the mobile monitoring device canrecord the time that the RTP packet was captured and can extract thepacket creation time from, for example, the RTP packet header. Themobile monitoring device can use these values to calculate an overalldelay that can then be used as an indicator of congestion. Thecongestion indicator can be associated with, for example, the mobileterminal that created the RTP packet, a mobile monitoring device thatcaptured the RTP packet, and/or the wireless network over which the RTPpacket was transmitted. In some embodiments, the mobile monitoringdevice that calculated the congestion indicator can send the value to,for example, a central server for distribution to a user such as anetwork administrator.

In several embodiments, the overall delay 450 can be calculated using acombination of one or more delays (e.g., transmission delay, processingdelay) through one or more access points and/or one or more mobileterminals. Values for certain portions of the overall delay can beestimated and/or subtracted from the overall delay, if necessary. Also,in some embodiments, individual delays (e.g., transmission delay,back-off delay, processing delay) from one or more devices can becombined in any appropriate combination to make up an overall delay.

If the processing delay 452 and the transmission delay 456 are quitesmall (i.e., negligible) and/or constant compared with the back-offdelay 454, the processing delay 452 and the transmission delay 456 canbe subtracted from the overall delay 450 to obtain a measure of theback-off delay 454. If the processing delay 452 and the transmissiondelay 456 are subtracted from the overall delay 450 (assuming these arethe only three delays), the overall delay 450 will be substantiallyequal to the back-off delay 454. For example, the transmission delay 456and processing delay 452 can be estimated and subtracted from theoverall delay 450 to obtain a value that is substantially equal to theback-off delay 454. The transmission delay 456, for example, can beestimated by multiplying minimum packet size with transmission speed.The processing delay 452 can be estimated, for example, based onmeasured processing capability and/or traffic load. These values can beobtained from information in one or more captured RTP packets.

Although calculating the back-off delay 454 was relativelystraighforward in the scenario shown in FIG. 4, obtaining the back-offdelay 454 for use as a congestion indicator can be complicated, forexample, when the calibration of one or more time clocks is necessary.For example, in some embodiments, the mobile terminal creating an RTPpacket can send RTP packets from a time zone that is different than thatassociated with a capturing device. Also, in some embodiments, the unitsused to measure time within a mobile terminal can be different than theunits used to measure time by a capturing device. For example, a mobileterminal can measure time based on codec size and/or RTP payload whiletime as measured by a capturing device can be based on real-time (i.e.,absolute time). In scenarios such as these, a time clock associated withthe mobile terminal can be calibrated with (i.e., synchronized oradjusted to correspond with) a time clock associated with the capturingdevice so that delays will be calculated accurately and/or in a modeuseful, for example, for a user. The calibration of time clocks forcalculation of a congestion indicator using back-off delay is describedin FIGS. 5-6.

FIG. 5 is a graph that illustrates an example embodiment where a minimumoverall delay, D_(min), is used to the calibrate a time clock of acapturing device (e.g., mobile monitoring device) with a time clock of amobile terminal. The time clocks are calibrated so that aftercalibration, the calculated overall delays, d, will not only besubstantially representative of back-off delay (an indicator ofcongestion) but will also be calibrated (i.e., real-time) rather thanrelative. An overall delay, d, that is calculated based on a calibrationtechnique can be referred to as a calibrated overall delay. When thetime clocks are not calibrated only relative delay measurements can becalculated. In some embodiments, a congestion indicator can be based ona relative overall delay measurement rather than a calibrated overalldelay measurement.

As shown in FIG. 5, time line 500 shows the packet creation times (PCTs)for PCT₀ through PCT(n) where PCT(n) is the packet creation time, PCT,of the n^(th) packet according to the time clock of the mobile terminal.Time measurements related to time line 500 increase in a downwarddirection. Time line 510, which shows time increasing in a downwarddirection, shows the packet capture times (CAPTs) for CAPT₀ throughCAPT(n) where CAPT(n) is the packet capture time of the n^(th) packetaccording to the time clock of the capturing device. The figure showsthe overall delays d(g) through d(n) which are the overall delays, d,for the g^(th) through the n^(th) packets, respectively.

The time clocks associated with the mobile terminal and the capturingdevice are calibrated by, first, determining a minimum value of overalldelay, D_(min), and then using D_(min) to adjust the time clock of thecapturing device. The minimum overall delay, D_(min), is determined froma sample of overall delays, d, calculated during a calibration timeperiod 520 shown in FIG. 5. The overall delays, d, are the differencebetween the PCTs from the mobile terminal and corresponding CAPTs fromthe capturing device. Because the time clocks of the mobile terminal andthe capturing device are, in this embodiment, not initially calibratedwith one another, the overall delays, d, calculated during thecalibration time period 520 are relative to one another and notcalibrated (i.e., real-time).

Because back-off delay is variable and because transmission andprocessing delays can be assumed to be constant (and/or small) comparedwith back-off delay, if the calibration time period is long enough,eventually one or more RTP packets with little or substantially zeroback-off delay will be found. The RTP packet with the minimum overalldelay, D_(min), will substantially correspond with a packet that hasonly processing delay and/or transmission delay. The probability thatD_(min) will represent only the processing and/or transmission delaysdepends on, for example, the length of the calibration time period 520and the level of traffic load in a wireless network during that period.The calibration time period 520 can be chosen so that D_(min)substantially represents only processing and/or transmission delays. Byadjusting the time clock of the capturing device by D_(min), subsequentdelays, d, calculated using the difference between the PCTs and CAPTswill be substantially representative of only back-off delay. In someembodiments, the calibration time period can be, for example, 1 secondand in other embodiments, the calibration time period can be, forexample, 24 hours.

FIG. 5 shows that from all of the overall time delays d(g) through d(n)calculated during the calibration time period 520, d(i) is determined tobe the minimum overall delay, D_(min). At time 530, the time clockassociated with the capturing device is adjusted (i.e., calibrated) byD_(min) so that subsequent delays, d, will be calibrated and willsubstantially represent back-off delay. The overall delay, d(o), whichis the difference between PCT(o) and CAPT(o), is calculated using theadjusted time clock of the capturing device. The overall delay, d(o) isa calibrated overall delay (i.e., real-time overall delay) that issubstantially representative of back-off delay and can be used as anindicator of congestion.

Although in this embodiment, the time clock associated with thecapturing device is adjusted forward by D_(min), in some embodiments,the time clock associated with the mobile terminal and/or the capturingdevice can be adjusted, if necessary. In yet other embodiments, theuncalibrated overall delays can be adjusted by the minimum overall delay(e.g., subtract the minimum delay) to derive an calibrated overalldelay. In these scenarios, time clocks associated with the mobileterminal and/or the capturing device do not need to be adjusted.

In some embodiments, the minimum overall delay can be updated and usedto adjust delay calculations continuously as smaller minimum delays arefound during normal wireless network operations. In other embodiments, amobile terminal and capturing device can synchronize their respectivetime clocks with a network timing protocol (NTP) server so thatcalculated delay values for packets can be based on a synchronized time.In several embodiments, a minimum overall delay can be first estimatedand then updated with overall delay values collected during normalwireless network operations. For example, the transmission delay can beestimated based on a minimum packet size and/or transmission speed andthe processing delay can be estimated based on a measured processingcapability and/or traffic load.

FIG. 6 is a flowchart that illustrates a method for calculating acongestion indicator based on a minimum time delay. The figure showsthat, first, a calibration time period is set at 600. The calibrationtime period is set so that a high probability exists that a minimumdelay can be found that substantially represents only processing and/ortransmission delays. After the calibration time period is set at 600,packets are received (i.e., captured) during the calibration time periodand overall delays are calculated 610. From the group of overall delayscalculated using information from captured packets during thecalibration time period, a minimum time delay is determined 620.

A packet(s) is then received (i.e., captured) and a calibrated overalldelay is calculated based on the minimum time delay value at 630. Theminimum time delay value can be used to calibrate the time clocks of,for example, a mobile terminal and/or a capturing device so that theoverall delay calculated using parameters associated with the capturedpacket will be substantially representative of back-off delay. In someembodiments, the minimum delay can also be subtracted from an overalldelay value calculated using a packet creation time and packet capturetime that are not calibrated with one another.

After the calibrated overall delay is calculated at 630, the calibratedoverall delay is used to generate (i.e., calculate) a congestionindicator 640. The congestion indicator can be a value that is derivedusing, for example, any appropriate mathematical algorithm based on thecalibrated overall delay. Finally, the flowchart shows that thecongestion indicator is associated with a device (e.g., mobile terminaland/or capturing device) and/or a wireless network (e.g., wireless LAN)at 650.

In some embodiments, a congestion indicator can be generated using morethan one calibrated overall delay value calculated using data associatedwith more than one captured packet. The congestion indicator can becalculated using a mathematical combination of calibrated overallvalues, such as, for example, a mean calibrated overall value. Also, inseveral embodiments, a congestion indicator can be sent to anotherdevice for use by, for example, a user. In other embodiments, theminimum overall delay value can be updated continuously as packets arecaptured to calculate calibrated overall delay values. The congestionindicator can be updated as the minimum overall delay value is updatedand/or as calibrated overall delay values are calculated. In yet otherembodiments, packets that are received can be filtered so thatcalibrated overall delay values are calculated using only selectedpackets.

CONCLUSION

In conclusion, an apparatus and method for measuring quality metricsassociated with a wireless network is described. While variousembodiments of the invention have been described above, it should beunderstood that they have been presented by way of example only andvarious changes in form and details may be made.

1. A method, comprising: capturing, at a capturing device, a packettransmitted over a wireless network; and calculating a congestionindicator based on a delay associated with the packet.
 2. The method ofclaim 1, further comprising: receiving a creation time of the capturedpacket, the creation time is indicative of a time the packet was createdby a mobile terminal; determining a capture time of the packet at thecapturing device, the capture time is indicative of a time the packetwas captured by the capturing device; and determining the delay based onthe capture time and the creation time.
 3. The method of claim 1,further comprising calculating the delay using a minimum delay.
 4. Themethod of claim 1, further comprising: calibrating a first time clockassociated with the capturing device with a second time clock associatedwith a mobile terminal based on a minimum delay, the delay is calculatedbased on the minimum delay, the minimum delay is determined based on aplurality of delays determined during a calibration time period.
 5. Themethod of claim 1, further comprising: calibrating a first time clockassociated with the capturing device with a second time clock associatedwith a mobile terminal based on a minimum delay, the packet is a firstpacket, the delay is a first delay that is calculated based on theminimum delay; and updating the minimum delay based on a second delayassociated with a second packet.
 6. The method of claim 1, wherein thedelay is an overall delay that includes at least one of a processingdelay, a back-off delay, or a transmission delay.
 7. The method of claim1, wherein the wireless network is at least one of an ad-hoc wirelessnetwork or an infrastructure wireless network.
 8. The method of claim 1,further comprising: associating the congestion indicator with at leastone of an access point, a mobile terminal, or the wireless network. 9.The method of claim 1, wherein the packet is selected from a pluralityof packets based on a filter criteria.
 10. A method, comprising:capturing, at a capturing device, a packet transmitted from a mobileterminal over a wireless network; and calculating a quality metric basedon a value of a parameter associated with the packet.
 11. The method ofclaim 10, further comprising selecting the packet from a plurality ofpackets based on a filter criteria.
 12. The method of claim 10, furthercomprising associating the quality metric with at least one of thecapturing device, the mobile terminal, or the wireless network based onthe parameter.
 13. The method of claim 10, further comprisingdetermining the value of the parameter at the mobile monitoring device.14. The method of claim 10, wherein the wireless network is configuredas at least one of an infrastructure wireless network or an ad-hocwireless network.
 15. The method of claim 10, wherein the quality metricis at least one of a delay metric, a jitter metric, a congestion metric,a packet loss metric, or a transport quality-of-service metric.
 16. Anapparatus, comprising: a wireless receiver module configured to receivea packet transmitted over a wireless network; and a processor configuredto calculate a congestion indicator based on a delay associated with thereceived packet.
 17. The apparatus of claim 16, further comprising: awireless transmitter module configured to respond to a beacon signaltransmitted by an access point, the wireless receiver module receivesthe beacon signal.
 18. The apparatus of claim 16, further comprising: amemory configured to store a filter criteria, the packet is selected bythe processor based on the filter criteria.
 19. The apparatus of claim16, wherein the processor is configured to calculate the delay based ona creation time associated with the packet and a capture time of thepacket, the creation time indicates when the packet was created by amobile terminal, the capture time indicates when the packet was capturedby a capturing device.
 20. The apparatus of claim 16, wherein theprocessor is configured to calibrate a first time clock associated witha capturing device with a second time clock associated with a mobileterminal based on a minimum delay, the delay is calculated based on theminimum delay, the minimum delay is determined based on a plurality ofdelays calculated during a calibration time period.